Take-off device for aeroplanes



June 24, 1930.

D. CANFIELD I 1,767,120

,TAKE-OFF DEVICE FOR AEROPLANES Filed Nov. 26, 1928 2 Sheets-Sheet l June 24, 1930.

D. CANFIELD TAKE-OFF DEVICE FOR AEROPLANES Filed Nov. 26, 1928 2 Sheets-She et 2 M 3 m V Patented June 24, 1930 UNITED STATES :PATENr nnnnnyoamrmnn, or nnlwauxna, wisoonsm ran-oar nEvr'en ron anaor auas Application filed November 26, 1928. Serial No. 321,902.

This invention relates to take-oft devices for aeroplanes.

In aeroplanes, it is sometimes the case that the pilot has to rise within a very short distance in order to avoid obstructions. This limited space frequently precludes the possible take-off of the aeroplane and the machine has to be towed to a longer runway. This invention is designed to overcome the defects noted, and to provide a novel form of take-off device which is so constructed that it permits the aeroplaneto rise after a veryshort run, so that it may readily clear obstruct-ions in a limited runway and, therefore, which provides greater facility to];1 taking ofi' than has heretofore been possi e.

Further objects are to provide a device which is under the control of the operator although having automatic parts, and which is so constructed that the wheels or pontoons are shot downwardly from the machine. to thus suddenly elevate the machine andprfoject it upwardly a distance fromthe ground or water and thus aid materially in the shortening of the distance required for the initial run.

Further objects are to provide a device havingthe characteristics noted above which does not impose an additional load upon the driving motors, but which operates wholly independently of the driving motors and through the agenc of a landing and take-ofl' gear operated yv an" explosive device independently ofthe m'otor.

" An embodiment of the invention is shown in the accompanying drawings in which:

Figure 1 is a side elevation of the aero-- plane showing it in its normal position;

Figure 2 is a view of the aeroplane just after it has taken ofi showing in dotted lines the path traversed by the center of the axl of the landing wheels;

Figure 3 is a fragmentary sectional view through one side of the take-off mechanism; Figure 4 is a fragmentary view of the structure shown in Figure '3 taken at right angles to such figure; a i 0 F'gure 5 is a sectional view through the upper end of one of the take-off cylinders showing the valves in section. Referring to the drawings, it will be seen that a conventional form of aeroplane body is indicated by the reference character 1.' This body is provided with braced hollow studs or strutsv 2 on opposite sides. These struts, in the usual construction of aeroplanes, carrying the landing gear, which may be either pneumatic wheels or pontoons. For the sake of simplicity, wheels only have been shown, although it is to be distinctly understood that the invention is not limited to wheels but is also applicable to hydroplanes equipped with pontoons. In this construction, the axle 3 for the. landing wheels 4 is not carried directly by the bracing or struts 2, but is carried by means of vertical piston rods 5 located at opposite sides of the machine, as is apparent from Figures 3 and4. These piston rods extend upwardly through a fitting 6 secured to the frame-work of the machine. This fitting carries a compression spring 7 which .normally is inactive, and merely loosely surrounds the piston rod 5. The upper end of the piston rod is rigidly attached to a piston 8 which slidably fits within the cylinders 9.

The cylinders 9 will hereinafter be referrezl to as the take-off cylinders.

This construction is duplicated on opposite sides of the machine. The take-ofl cylinders 9 are provided with outlet ports 10.

which communicate with an outlet channel 11 adjacent the lower end of the cylinder. This outlet chamber or channel. 11 is provided with a discharge pipe or exhaust pipe 12 which projects downwardly below the v machine.

The cylinder is adapted to be supplied .with compressed airand compressed gas or other fuel by meansof the valves 13 and 14, respectively, hereinafter described in greater detail, and this explosive mixture is ignited by means of the spark plu 15. The ignition of this mixture projects e pistons downwardly on opposite sides of the machine and thus suddenly forces the body of the machine upwardly, as the downward motion is resisted by the wheels'eontacting 199 with the ground. Thisdownward motion of the piston continues until the pistons strike the springs 7 which act as cushions and relieve theshock of the blow.

The piston rods 5 are provided with lugs or cam members 16 which are engaged by [the latches 17. These latches are urged towards locking position by means of the the member '20. The member 20 is provided with a valve seat adapted to be closed by the valve 22. This valve 22 is provided with a stem 23 guided in the member 21, as shown.

Further, the stem carries a plate 24 against which a compression spring 25 bears, the

other end of the spring resting u on the member 20. The casing formed of t e mem-' bers 20 and 21 is supplied with compressed air through the medium of the compressed air pipe 26. This. flow of compressed air is controlled by means of the valve 27 in the compressed air line. The compressed air is drawn from any sultablesource, for 1nstance, the compressed air tank 28, (see Figure 2).

' It is to be noted from reference to Figure 5 tha t a'pipe 29 leads into the compressed a1r p1pe 26 at a pointbeyond the valve 27. This pipe 29 communicates with a supply of lubricating oil, so that when the valve is opened, the oil is sucked into the flowing stream of air and projected into the cylinder.. Preferably, the valve 27 for each of the air pipes is provided with a lever 30 which is connected with an operating bar 31. This operating bar joins the levers of the two valves and is under the control of the pilot.

The fuel inlet valve is provided with a casing formed of the inner .member 32 screwed into the cylinder and provided with a valve seat which cooperates with the valve 33. A second casing 34 is bolted tothe casing 32 and a third casing 35 issecured to the casing 34. Within the casing 35a sliding plun er 36 is positioned and is urged out-. war lyby means of the sprin 37. This plunger is provided with a va ve end 38 which cooperates with a valve seat formed on the casing 34, as shown in Figure 5. The plunger is also provided with a screw threaded aperture into which the hollow stem 39 of the valve33 projects. This hol-' lowstem is provided with a plurality of zfipelrtures 40 for the escape of, the pressure It is to be noted also from Figure 5, that reference character 48.

a spring 41 urges\the valve stem 39 outwardly towards valve closing position.

Within the plunger 36 a valve seat 42 is formed and is closed normally by. the screwthreaded valve 43. This screw. threaded valveis held against axial shifting by means of the stationary member 44. It may be rotated to thus force the plunger 36 and the valve 33 downwardly or inwardly to the position shown in Figure 5. It may also be rotated in the opposite direction to permit the closing of the valve 33 and the opening of the valve 38. Y

The stem 43 is provided with a fuel aperture 45 which communicates with a fuel supply pipe 46 leading toa tank 47 adapted to contain the fuel under ressure.

The lever for rotating t e valve stem 43 is indicated in Figure 3 by means of the These levers v48 are joined by means of a transverse rod, a por-, tion of which is indicated by the reference character 49 in Figure 3.

The operation of the gas valve is as follows: 1*

The levers 48 are rocked so as to rotate the' screw threaded valve stem 43. This .forces the plungers 36 inwardly and unseats .the valves 33. Also, it moves quickly opening the valves 27 and scavenging of the cylinders of burnt .gases and filling them with fresh air. The fuel-"under pressure is thus rojected-into the-cylinder and mixes with t e fresh air. f

This operation is performed while the machine is in flight and while the piston rods 5 are held down by the catches 17.

When it is desired to land the pilot pulls upon the cords 19, thus releasing the catches, and when the machine strikes the groundthe wheels 4 transmit. pressure upwardly through the piston rods 5 and force the pis- -tons 8 into their uppermost positions, thuscompressing the charge due to the weight of the machine.

When it is desired to again take ofi,'the 'ilot starts the motors and when the motors have attained suflicient speed, he ignites the charges in the cylindersby closing the appropriate circuit and causing a spark at the plugs 15. This causes the sudden downwardprojection of the wheels which are in contact with the ground. The result is that I the bod of the machine is suddenly shot upward y into an elevated position, as shown in Figure 2. At the. downward stroke of the piston rods, the catches 17 again come into play and lock them in their lowermost positions. The pistons move past the ports 10 and allow discharge of the I burnt gases. Scavenging is eflected,'as previously described, and the same cycle of operations is repeated. It will be seen that a novel form of takeoff device for aeroplanes has been provided which enables the pilot to take off with a very much shorter run than has heretofore been possible, as means are provided for suddenly projecting the aeroplane bodily upwardly from the ground while it is in motion.

While the invention has been shown as applied to a land machine it is equally applicable to an hydroplane'and, therefore, the term wheels or a similar expression appearing in the claim, is intended to cover wheels, ontoons, or other landing elements.

Although the invention has been described in considerable detail, such description is intended as illustrative rather than limiting as the invention may be variously embodied and as the scope of such invention is to be determined as claimed.

I claim: 7

In an aeroplane, hollow struts extending downwardly, a supporting axle at the lower end of the struts, piston rods connected to the axle adjacent the ends thereof, cylinders supported by the frame of the aeroplane havlng closed bottom walls, a piston connected to each piston rod and operating in the cylinders, a coil spring at the closed end of'each cylinder against which the piston abuts, a spring-pressed catch member adjacent each piston rod and acam member carried by each rod for engagement by the 40 catch when the pistons are in the lower ends of the cylinders for retaining said piston rods in a projected position,- and means for manually releasing the catch members whereby the tension of the springs in the Jylinders will cause the pistons to be returned to the opposite ends of the cylinders and return the axle to a normal position adjacent the lower ends of the struts.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee,

in the county of Milwaukee and State of Wisconsin.

DUDLEY CANFIELD. 

